not too sure but i think "blisters" (the more commonly used term) covers for both khatira and foka (due to burning or irritation)

In medical terminology, the symptoms: redness, itching and dryness, blistering, oozing and bleeding are all attributed to the form of a dermatitis(skin disease) called eczema, but that's more specific and not all blisters are caused by eczema. I heard that eczema is a common disease among us Nepalese though just like gastric is :P

anyways, hope that helps...

any docs out there? correct me if i am wrong :D